This application claims the benefit of Korean Application No. 2002-37608, filed Jun. 29, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to microwave ovens, and more particularly, to a door provided on a microwave oven for closing or opening a cooking cavity of the microwave oven.
2. Description of the Related Art
Generally, a microwave oven is an electrically operated oven having a magnetron which generates high-frequency electromagnetic waves (xe2x80x9cmicrowavesxe2x80x9d) with a fundamental frequency of 2450 MHz. The microwaves generated by the magnetron are radiated into a cooking cavity to repeatedly change a molecular arrangement of moisture existing in food, thus generating an intermolecular frictional heat within the food to cook the food.
FIG. 1 shows a conventional microwave oven having a cabinet 1 which establishes an outer appearance of the microwave oven. The cabinet 1 includes a cooking cavity 2 and a machine room (not shown) which are partitioned from each other. The cooking cavity 2 receives food to be cooked, while the machine room contains a variety of electrical and electronic devices, such as a magnetron (not shown) and a high voltage transformer (not shown).
When the microwave oven is turned on, the magnetron generates microwaves which are radiated into the cooking cavity 2 to cook the food laid in the cooking cavity 2.
The cooking cavity 2 of the microwave oven is opened at a front thereof to allow a user to place and remove the food from the cooking cavity 2. A door 3 is hinged to the cabinet 1 to close or open the cooking cavity 2.
The door 3 is designed such that the door 3 comes into a close contact with a front wall of the cabinet 1 so as to prevent a leakage of the microwaves from the cooking cavity 2 through a junction of the cabinet 1 and the door 3.
However, with use over a period of time, the door 3 may become deformed and an undesired gap may form at the junction of the cabinet 1 and the door 3. In such a case, the microwaves undesirably leak from the cooking cavity 2 through the gap.
Accordingly, it is an aspect of the present invention to provide a microwave oven which effectively prevents a leakage of microwaves from a cooking cavity through a junction of a cabinet and a door of the microwave oven.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
To achieve the above and other aspects of the present invention, there is provided a microwave oven comprising a heating unit to cook food, a cabinet which establishes an appearance of the oven, and a cooking cavity which is defined in the cabinet and includes an opening at a front thereof, wherein the cabinet includes a first door which opens and closes the opening of the cooking cavity, and a second door which is installed in front of the first door and covers and uncovers the front of the first door.
The first door may rotatably be hinged to a side edge of the cabinet so as to rotate left and right to open and close the opening of the cooking cavity, and the second door may be rotatable upward and downward to cover and uncover the front of the first door.
The second door may comprise an upper door part hinged to an upper portion of the cabinet, and a lower door part hinged to a lower portion of the cabinet, wherein the upper and lower door parts of the second door are fitted together or separated from each other to cover or uncover the front of the first door.
The cabinet may further include a projecting base which projects from a lower portion of the cabinet. The upper door part of the second door may cover both a top portion of the first door and an upper portion of the front of the cooking cavity, and the lower door part of the second door may be hinged to the projecting base of the cabinet.
The second door may be wider than the first door by a predetermined width, and may be curved in a vertical direction with respect to a base of the cabinet to cover both a front portion and an upper portion of the first door.